This invention relates generally to prosthetic devices and methods of manufacture, and more specifically, to maxillofacial prosthetic devices and dental appliances having permanent silicone elastomers bonded thereto forming composite structures with enhanced strength, dimensional stability and elasticity.
Prosthodontic devices, such as dentures typically consist of a baseplate of a hard resin, such as poly(methyl methacrylate) which supports the artificial teeth for chewing, and also enhances esthetics. Difficulty can arise, however, due to the inability of patients to tolerate the hard baseplate. As a result, there is need for a resilient liner which may be affixed to the denture base to cushion soft tissues of the oral cavity. Ideally, such materials should be permanently resilient, inert, cleanable, substantially water insoluble, have low water-sorption properties and good tensile and tear strength. While softness is desirable for comfort, the liner must also be sufficiently firm to displace soft tissues of the mouth and permit grinding of the denture periphery to avoid creating sore spots. From a practical view point, the dental appliance should also be capable of fabrication under conditions generally found in dental laboratories, avoiding extremes in temperature and pressure, or the need for special equipment.
Laboratory and clinical studies have shown that few, if any, of the present materials used as resilient liners and prosthetic devices, for example, are satisfactory in all respects. Most common shortcomings include inadequate strength and elasticity, high rate of water diffusion through the elastomer and subsequent staining and deterioration. Frequently, with the discovery of a potentially improved prosthodontic material having what might appear to be fewer of such shortcomings, the material is compromised due to the inability to satisfactorily bond the elastomer to dental base plastics and other prosthetic appliances.
Accordingly, there is a need for improved facial and dental prosthetic elastomeric materials possessing properties of strength, elasticity, dimensional stability, low water sorption and toxicity, including methods which enable convenient bonding to most dental base polymers with a high degree of permanence and reliability. Such materials and methods would be useful in fabricating prosthodontic devices, such as dentures with improved elastomeric liners for preventing and treating chronic tissue irritation from hard dental polymers and for cushioning soft tissues; liners after oral surgery, maxillofacial prosthetic devices, like obturators for defects in the palate, and the like.